Ex Situ Perfusion of Human Limb Allografts for 24 Hours.

BACKGROUND: Vascularized composite allografts, particularly hand and forearm, have limited ischemic tolerance after procurement. In bilateral hand transplantations, this demands a 2 team approach and expedited transfer of the allograft, limiting the recovery to a small geographic area. Ex situ perfusion may be an alternative allograft preservation method to extend allograft survival time. This is a short report of 5 human limbs maintained for 24 hours with ex situ perfusion. METHODS: Upper limbs were procured from brain-dead organ donors. Following recovery, the brachial artery was cannulated and flushed with 10 000 U of heparin. The limb was then attached to a custom-made, near-normothermic (30-33°C) ex situ perfusion system composed of a pump, reservoir, and oxygenator. Perfusate was plasma-based with a hemoglobin concentration of 4 to 6 g/dL. RESULTS: Average warm ischemia time was 76 minutes. Perfusion was maintained at an average systolic pressure of 93 ± 2 mm Hg, flow 310 ± 20 mL/min, and vascular resistance 153 ± 16 mm Hg/L per minute. Average oxygen consumption was 1.1 ± 0.2 mL/kg per minute. Neuromuscular electrical stimulation continually displayed contraction until the end of perfusion, and histology showed no myocyte injury. CONCLUSIONS: Human limb allografts appeared viable after 24 hours of near-normothermic ex situ perfusion. Although these results are early and need validation with transplantation, this technology has promise for extending allograft storage times.

Body proportions as possible predictors for free gracilis one-stage facial reanimation.

BACKGROUND: Gracilis muscle and its motor nerve belongs to most commonly used flap for facial reanimation. However, it is performed in two steps, which is time consuming. One stage technique can be also performed, but the length of the motor nerve cannot be currently determined before surgery. AIM: The present study was conducted in order to evaluate the body composition on the length and suitability of the motor nerve of gracilis muscle for one stage facial reanimation. METHODS: The gracilis flaps along with the motoric nerve were dissected from 20 fresh cadavers (6 females, 14 males). The length of the lower extremity from superior iliac anterior spine to the bottom of the heel and BMI were measured. Regression analysis of lower extremity length and BMI to the actual length of the motor nerve of gracilis flap was performed. RESULTS: The linear regression analysis showed a positive correlation between the length of the lower limb and the size of the motor nerve length (r = 0.5060, p < 0.05), as well as between the BMI and the size of the motor nerve length (r = 0.5073, p < 0.05). Also, the males had longer motor nerve when compared to females by 13 % (p < 0.05). No difference between females and males in BMI was observed. CONCLUSION: The length from the superior iliac anterior spine, BMI and gender seemed to be potential factors that could help to predict the length of the gracilis flap motor nerve for the one stage facial reanimation. However, further studies evaluating other anatomical factors and validating the possible prediction rule for one stage reanimation success are needed (Fig. 3, Ref. 14).

Reconstruction of Large Abdominal Wall Defects Using Neurotized Vascular Composite Allografts.

BACKGROUND: Abdominal wall vascularized composite allotransplantation is the second most common form of vascularized composite allotransplantation. Sensory and functional recovery are expected in other forms but have never been demonstrated in abdominal wall vascularized composite allotransplantation. The authors hypothesize that coaptation of two thoracolumbar nerves will result in reinnervation of the alloflap and maintenance of the muscle component. METHODS: Adult, male, 10-week-old Brown Norway and Lewis rats were used for experiments. The rat donor's common iliac vessels were anastomosed to the recipient's femoral vessels. Intercostal nerves T10/L1 were coapted. Four groups (n = 5 per group) were included for study: group 1, Lewis, intercostal nerves cut, not repaired; group 2, Lewis intercostal nerves cut, T10/L1 repaired; group 3, allogeneic Brown Norway-to-Lewis abdominal wall vascularized composite allotransplantation, T10/L1 repaired; and group 4, syngeneic Lewis-to-Lewis abdominal wall vascularized composite allotransplantation, T10/L1 repaired. Animals were killed on postoperative day 60. Nerve regeneration was assessed using muscle weight analysis, myofibril cross-sectional area, nerve histomorphometry, and neuromuscular junction percentage reinnervation. RESULTS: Groups 2, 3, and 4 maintained a significantly greater percentage of postharvest weight compared with group 1 (p < 0.05). Group 1 had significantly decreased myofibril cross-sectional area compared with controls (p < 0.05). There was no significant difference in myofibril cross-sectional area in groups 2 through 4 compared with controls (p > 0.05). Group 1 had significantly decreased percentage reinnervation of the alloflap compared with controls (p < 0.05). There was no significant difference when comparing group 2 through 4 with internal, contralateral controls (p > 0.05). CONCLUSION: In a murine model for abdominal wall vascularized composite allotransplantation, coaptation of T10/L1 will allow for reinnervation of the alloflap and maintenance of the muscle component.

A functional periorbital subunit allograft: vascular, anatomic, and technical considerations for future subunit facial transplantation.

BACKGROUND: Injury to the face can result in the loss of critical specialized structures (the eyelids, lips, ears and nose). Vascularized composite allotransplantation (VCA) allows the surgeon to replace exactly what has been lost. The success of the clinical face transplants suggests the possibility of transplanting specialized units of the face. In this study we explore the neurovascular anatomy and technical specifics for harvest of a functional composite eyelid subunit flap. METHODS: 12 fresh cadaver heads were studied, each yielding two flaps (N = 24). The facial (FA) and superficial temporal arteries (STA) were cannulated and injected with a gelatin/acrylic dye mixture. 6 cadaver heads were evaluated via high-resolution three-dimensional CT scans with contrast. RESULTS: The dye injected into the STA uniformly stained the tissue of the eyelid/periorbital subunit. Injection into the FA resulted in staining of the skin and soft tissues in the medial canthal region and superior eyelid skin in 66% of specimens. CT scan studies confirm our findings with injection into the STA resulting in contrast infiltration of the palpebral arterial arcades in all cases. Injection of the FA resulted in contrast infiltration of the palpebral arterial arcades in 2 of 3 cases. CONCLUSIONS: Based this study, a periorbital flap can be based on the STA. Motor innervation of the flap is via the zygomatic and buccal branches of the facial nerve with sensory innervation via the infraorbital, supraorbital and supratrochlear nerves. FA could be used, but its ability to perfuse the entire flap was inconsistent.

Facial and hand allotransplantation.

Vascularized composite allotransplantation (VCA) is a novel therapeutic option for treatment of patients suffering from limb loss or severe facial disfigurement. To date, 72 hand and 19 facial transplantations have been performed worldwide. VCA in hand and facial transplantation is a complex procedure requiring a multidisciplinary team approach and extensive surgical planning. Despite good functional outcome, courses after hand and facial transplantation have been complicated by skin rejection. Long-term immunosuppression remains a necessity in VCA for allograft survival. To widen the scope of these quality-of-life-improving procedures, minimization of immunosuppression to limit risks and side effects is needed.

One-stage reconstruction of composite extremity defects with a sural neurocutaneous flap and a vascularized fibular graft: a novel chimeric flap based on the peroneal artery.

BACKGROUND: The fibula flap has been widely used for reconstruction of composite bone and soft-tissue defects. The skin paddle of the fibula flap has played a critical role in providing a cutaneous component and good monitor for the bone component. In this report, the authors designed a perforator-based sural neurocutaneous flap instead of a peroneal perforator flap to enlarge a skin paddle for wound coverage. METHODS: A novel chimeric flap was harvested based on the peroneal artery, and consisted of a sural neurocutaneous flap and a fibular graft. The sural neurocutaneous flap was elevated based on a single peroneal perforator and connected with the bone component by means of the peroneal artery. Two patients with complex bone and soft-tissue defects were treated by using this chimeric flap. In case 1, the radius defect was 8 cm in length and the soft-tissue defect measured 23 × 10 cm. In case 2, the distal radius was injured and the defect was 16 cm in length. The area of soft-tissue defect was 23 × 8 cm. In this case, the fibula head was used for wrist reconstruction. The soft-tissue defects in the two cases stretched across the palmar and dorsal surfaces of the forearm. RESULTS: The lengths of the bone components were 10 and 16.5 cm, respectively, and the areas of the skin components were 24 × 12 cm and 25 × 10 cm, respectively. Both chimeric flaps survived completely without complications. The follow-up period was 42 months in case 1 and 16 months in case 2. Complete bone union was observed in both cases, and no remarkable degeneration of the fibular head occurred in case 2. The sural neurocutaneous flap showed good texture match and contour. No serious donor-site complications occurred. The two patients were satisfied with their daily lives relative to the severity of their injuries. CONCLUSION: The chimeric flap composed of a sural neurocutaneous flap and a fibular graft by means of the peroneal artery is a good candidate for reconstruction of long bone defects associated with extensive soft-tissue defects in the extremities.